The present disclosure relates to a device, a data transfer system, and a data transfer method, and for example to a device, a data transfer system, and a data transfer method in conformity with USB (Universal Serial Bus) 3.1 Gen 2.
A data packet (DP) in an OUT transfer of the USB 3.1 Gen 1 (USB 3.0) is composed of two packets, i.e., a data packet header (DPH) and a data packet payload (DPP). Further, the transfer of the DP is performed in the order of the DPH and the DPP.
Here, in the USB 3.1 Gen 1, if some kind of packet error occurs in the DPH, the pair of the DPH and DPP is discarded in a link layer of a USB device. Therefore, since a protocol layer of the USB device does not receive a packet related to the error, no process that is performed when a packet error occurs is necessary in the protocol layer.
Further, In USB 3.1 Gen 2, which is a specification succeeding the USB 3.1 Gen 1, a Length Field Replica field is added in the DPH. Further, the specification is changed so that when a CRC value in the DPH is an erroneous value and the Length Field Replica field has a correct value, only the DPH is discarded in the link layer and the corresponding DPP is sent to the protocol layer (Universal Serial Bus 3.1 Specification Revision.1.0, Chapter 7 and 8).